Electric house-heating apparatus



May 15, 1951 J. J. ROUIS ETAL 2,553,212

ELECTRIC HOUSE-HEATING APPARATUS Filed Oct. 26. 1949 4 v ..5 ..Sheets-Sheet 1 FIG.- I

l". Kiln lnven tors JOSEPH J. RQUlS 8! ROBERT J. ROUIS m va May 15, 1951 J. J. ROUIS ETAL 2,553,212

ELECTRIC HOUSE-HEATING APPARATUS Filed Oct. 26, 1949 ..3 Sheets-Shet 2 FIG. 3

3 9 Inventors JOSEPH J. ROUIS 8:

ROBERT J. ROUIS Attorneys M y 15, 1951 J. J. ROUIS ETAL 2,553,212

- ELECTRIC HOUSE-HEATING APPARATUS Filed Oct. 26, 1949 s Sheets-Sheet s Attorneys Patented May UNITED STATES OFFICE Joseph J. Ro'uis and'Robe'rt J, Rom Greeneville,

Tenn., assignor's' to Earnest T. Rippetoe, Mc-

hawk, Tenn.

Application October 26, 1949; seams. 123,712

8 Claims.

This invention relates to house heating systerns of the steam or hot water type, and more particularly to systems of this character employing electric energy as the source of heat.

Steam or hot water house heating systems as heretofore commonly arranged comprise a boiler located in the basement, and fired' by oil, gas or coal. The hot water or steam is then distributed to radiators located in the different rooms by pipes'extending up from the basement.

Basements are expensive, and many low cost homes are constructed without basements. I In such cases it is difficult, if not impossiblato iind a suitable location for a furnace or boiler of the usual type.

One of the objects of the" present invention is to provide an electrically heated boiler of such size and construction that it may be installed in any desired location inany rocmin the house, or even in a closet. Using no fuel, our improved heating plant entirely eliminates the objectionable dust, dirt or fumes which generally accompany the operation of the common type of heating plant;

Another objection to the conventional house heating boiler is the fact that it takes a relatively long time, when started cold, before the radiators get hot. A further object" of the present invention is to provide a boiler of the flash type, which contains but a small amount of water, and which will raise the temperature of the radiators to the desired point in a relatively short time after being put in operation.

Our improved electrically heated boiler is ing is not only completely concealed, but is done at the factory where the units are assembled.

Receptacles are built into the panel and properly connected with the wiring, so that all theinstaller has to do is to connect the service line to the main switch, and plug the room thermostat and' circulating pump motor into the respective receptacles.

Our improved boiler is equipped with a pic-1 rality of independent heating elementsj and" the invention contemplates" so arranging the control system that when the boiler is cold, and

the current first turned on, all of the heating elements are energized; to quickly raise the tem-: perature of the water to the desired point, while thereafter the heat is maintained by energizing only a few of the heating elements, in sequence, one by one, as conditions may require. a

While the heatin elements are normally controlled by the room thermostat, we employ an aquastat to limit the temperature of the water to a safe value, and" a feature of the invention resides in the manner in which this limiting aquastat cooperates with the room thermostat to produce the desired results.

In order that the invention may be readily understood, reference is had to the accompany ing drawings, forming part of this specification, and in" which:

Fig. 1 is a front elevation of our improved assembled unit.

Fig. 2 is a transverse section taken substantially on the line 2-'-2 of Fig. 1, looking in the direction of the arrows.

Fig. 3 is a view of the unit shown in Fig. 1, partly in side elevation and partly in vertical section. g V Fig. 4 is a fragmentary sectional detail on an enlarged scale showing a portion of Fig. 3.

Fig. 5 is a schematic view illustrating how our improved unit is connected with a conventional hot water house heating system, the" unit itself being shown in full lines and the heating system in broken lines.

Figs. 6 and 7 are fragmentary front and side elevational views respectively of one of the mer- Fig. 8 is a circuit diagram showing the ar:

rangement of electrical heating units and the controls therefor, and

Fig. 9 is a circuit diagram illustrating the room thermostat and aquastat and the manner in which they cooperate;

v Referring to the drawings in detail and more particularly, first, toFigs. 1, 2 and 3 thereof; our improved assembled unit comprises a rigid panel i made of either wood or metal, prefer ably the latter. The edges of this panel are secured" to a marginal frame preferably formed of channel iron 2, welded to the back of the plate. This frame forms within itself a recess" or chamber at the back of the panel.

Mounted on" the'iront of the panel is a boiler 3'; This s preferably of elongated cylind, fcrm as shown, having a domed u per end a. This boiler is secured in position by brackets 4 welded to the boiler and bolted to the panel as clearly shown in Fig. 2.

As best shown in Figs. 3 and 4, the bottom of the boiler consists of a plate 31) welded to the sides of the boiler and positioned a substantial distance from the lower end thereof, so that the side walls extend below the bottom plate, forming a chamber or recess.

Passing centrally up through the bottom plate 31) and welded thereto is a pipe nipple 5, to the upper end of which is secured a dome shaped deflector 6, as clearly shown in Fig. 3.

A similar pipe is set into the top of the boiler and provided with a fitting 1 in the nature of a coupling or T.

Also mounted on the bottom plate 3b of the boiler and surrounding the nipple 5 and deflector 6 are a circular series of electric heating elements 8.

These are of the well known immersion type, such for example as those being offered commercially under the trade name Calrod. A series of holes or openings 3d is formed in the depending wall 30 at the rear side thereof, and electrical conductors 9 for supplying current to the heating elements 8 pass through these holes and through corresponding holes in the panel I to the rear side of the panel. Thus all of the electric wiring connected with the heating elements in the boiler is completely concealed and Wholly invisible when the panel is viewed from the front.

Also mounted on the front of the panel is a main switch box it, a fuse box ll and a control box l2. To satisfy the fire underwriters, the cable It extending from the switch box 3 to the fuse box l! is mounted on the front of the panel, but all other wiring hereinafter described is mounted on the back of the panel so that it is completely concealed from the front.

Referring now to Fig. 8, the control mechanism mounted in the box 12 includes what we shall call a modulating motor M. Motors of this kind are available commercially under the trade name Modutrol made by Minneapolis Honeywell Regulator Company. The motor consists of a casing in which is contained a high ratio speed reducing gearing, and to this gearing is connected a horizontally extending shaft 15. When the motor runs, this shaft turns very slowly, requiring several minutes to make one revolution or cycle. The motor casing also contains limit switches to stop the motor at the end of a predetermined angular displacement of the shaft i5. The casing further contains a built-in balanced relay and compensating potentiometer, all as well understood by those skilled in the art.

On the shaft l5 of the motor are mounted a series of cams I6, each of which, as shown in Figs. 6 and '7, is constructed with a pair of projections 16a and 6b. These projections are not only angularly displaced, as shown in Fig. 6, but are also laterally offset, as shown in Fig. 7. Each cam serves to tilt a mercury switch ll, held by a clip is journaled on a shaft I9. Each clip has a pair of arms 26 and 2| projecting therefrom, which arms are offset laterally from each other and positioned to be engaged by the projections its and it?) respectively. As will be readily understood, the result of this arrangement is that when the shaft l5 rotates in one direction the projection ifia serves to tilt the mercury tube switch I? one Way so as to close the circuit connected therewith, while when the shaft 15 rotates in the opposite direction the projection 55b will tilt the mercury tube the other way so as to open the circuit. It will be further understood that the various cams throughout the series are progressively angularly displaced with respect to each other so that as the shaft l5 rotates the mercury tube switches are tilted, one after another, in sequence.

The switch box it contains the main switch [do (see Fig. 8) to which the supply mains i8a are connected. The cable l3, extending from this switch, is connected to the lower end of a pair of bus bars 22 on which a series of plug fuses 23 are mounted in the usual manner. A pair of conductors 23a extend from the lowermost pair of fuses 23 to a transformer 2d connected to the motor [4, to supply current thereto.

In the diagram of Fig. 8 we have illustrated electric heating elements 8. One side of these elements is connected by wires 25 to the several fuses 23, wh le the other side of the heating elements is connected by wires 25 to one terminal of the mercury tube switches H. The other terminal of the switches is connected by wires 2i to the fuses 23. Thus the energization and deenergization of the heating elements is individually controlled by the several separate mercury tube switches l! which are, in turn, operated by the motor shaft l5.

The extent direction of rotation of the motor i4 is controlled by three wires 28 which extend to a special aquastat 28 mounted at the top of the boiler. This aquastat may be mounted directly on the boiler or on the fitting "i, as shown in Figs. 1 and 3.

The aquastat 29 is shown as having two sets of binding posts of three each. One set is connected with the conductors 28, as above de scribed, while the other set is connected by conductors 38 with a receptacle 3! which is mounted on the panel l, as appears at the upper lefthand corner of Fig. l. A 3-pole plug is connected to one end of a 3-wire cable 5! adapted to be plugged into the receptacle 3%, while the other end of the cable 5| is connected to a special room thermostat 59, as indicated in Figs. 5 and 8.

Also mounted on the boiler is a Well known form of aquastat 32 adapted to control the motor of the hot water circulating pump.

Our improved electrically heated boiler preferably operates on 22% volts and it is customary, in 220 volt service, to employ a neutral or ground Wire, indicated in Fig. 8 at i379, the arrangement being such that volts exists between this neutral wire and each of the 220 volt mains. For convenience, this neutral wire is connected to a ground plate 33, mounted in the fuse box and provided with a series of binding screws The hot water circulating pump motor usually operates on 110 volts and for this reason we connect one side of the aquastat 32 by a wire with one of the binding screws on the ground plate 33. The other side of the a uastat .32 is connected by a wire 35 with one terminal of a receptacle 31, the other terminal of which is connected by a wire 35 with one of the fuses 23. Thus 110 volts is supplied to the receptacle 3i. This is adapted to receive a plug, connected by a cable 49 with the circulating motor 4%, hereinafter more fully described. Instead of bringing the Wire 35 from the aquastat 32 directly to the receptacle 31, we prefer to make this wire in two branches and to unite the branches by a coupling 35 at the fuse box, as shown in Fig. 8. The re- 5:, ce'ptac'le: 31 is mounted. on" the panel= I as i'n-- dicatedlat the lower lefthand corner of Fig.1..

A temperature andipressure gauge 38 is also preferably mounted onthe boiler as usual.

As already mentioned, it will beunderstood 5:: that all wiring, both fromthe heating elements to the fuse boxand to the control box, as well as the wiring from the control box to theaquastatand receptacle 3i,.is disposed=on the'back of the panel within the frame 2. In order to protect l and conceal this wiring wesecure aback plateor cover 39 to the frame 2,-asshown in Figs. 2 and3, thus completely enclosing the-wiring. This cover plate is preferably made of insulating material such as fiber-board.

In Fig. 5 we have illustrated schematically a l-pipe hot water heating; system such as may be employed in connectionwithour improved electrically heated boiler. This system is shown as comprising an upwardly extending pipe M connected to the coupling 1, anexpansion tank- 32, a series of special fittings 43 in the pipe 4i, connecting this pipe with radiators 44, and a return pipe 45, connected with the nipple 5-as by means of a coupling lfla Inthe return pipe 45 is preferably connected'a circulating pump 46. Water is supplied to-the system from-a pipe at through the usual automatic feed and relief valve-48.

Assuming the existence of such a hot water heating system in a house to-be heated, our improved unit can be installed simply by connecting the pipes 4i and 45to the fittings 1 and 5 respectively, as indicated in Fig. 5, andplugging in the water circulating pump 38 and room thermostat 53 by means of the cables at and 5% respectively.

Our improved assembledunitcan be installed at any point in the house which is-mostconvenient, such for example as in one of the upstairs rooms, or even in a closet. All-the ins-taller has to do is to bolt the panel of our unit tothe wall and make the above mentioned pipe connections, and the system is thenready to operate as soon as the power supply is "connected to the ,5 switch box.

By reference to Fig; 3 it will be seenthatthe water entering the boiler through nipple 5 is deflected laterally in all directions by the-dc flector 6, so that it flows upwardly around and in contact with all of the heatingelements 8 and thence out through the fitting 1. Due" to this deflection of the incoming water toward and around the heating elements-andalso-because of the fact that the boiler is -r'elatively small, the 5 water is heated very rapidly. By way of example, in a heating system for an average size fi-room house, where a power input of about 25 kilowatts is employed, it has been found that the radiators can be brought to a' temperature of 180 F. in approximately nine minutes.

A brief description of the operation of-the system will now be given, reference being had mainly to the diagrams of Figs. 8 and 9. y

it will be seen that the motor l4 iscontrolled 5 by a 3-wire circuit extending to and through the aquastat 2Q to the room thermostat 50. In commercial practice these three wires are usually colored red, white and blue; for'identification, and they will be so referred to in the following description. In the drawings these wiresare designated R, W and B, respectively.

It will be observed that the aquastat 29 is -pro vided with two sets of terminals of three each By reference-t0 Fig. 9:it wi1l:be further seen -that systems 6 the respective pairs of red--" terminals and of white terminals are permanently bridged or connected together. It will also be seen that between the blue terminals is arranged-a switch; member 55 adapted to engage a contact-54. It" will be still further seen that'a second switch; member 5"! connected with the white'terminal is-adapted to engage a contact 56 connectedwith" the red terminal. Itwill be understood, of course, thatthe switchmembers Stand 5-? move upwardly in respcnseto the occurrence of a pre'' determined temperature. The switch member 5'5 is normally out of engagement with its con tact 54, while the switch member 51 is normally in engagement with its contact 56. Thus the blue circuit is normally interrupted, andthe' red and white circuits are normally con nected. Upon the occurrence of the predetermined temperature, the two switch members move upwardly together, thus closing the blue circuit at Hand breaking the connection between thewhite and red circuits. An aquastat of this nature is commercially available under the designation Type L270, made by Minneapolis- Honeywell Regulator Company.

The rcom thermostat 50 may be described as a modulating thermostat and includes a poten-'-' tiometer 512, over which moves aslide 53. Thermostats of this kind are commerciallyavailable under the designation Type T92, made by Minneapolis-Honeywell Regulator Company. As is well understood, the potentiometer 52- in' this" thermostat cooperates with the compensating potentiometer in the motor it to constitute a Wheatstone' bridge. The slide is operated by a. bellows and the temperature which itis-desired. to maintain is determined by varying the tension of a spring which opposes the action of the bellows.

When the bridge is balanced, the relay in themotor I 2. occupies a neutral position. When the bridge becomes unbalanced the relay moves one way or the other, thus causing the motor to run. in one direction or the other.

When the system is cold, the slide 53 is; of course, at one extreme end of its travel, and the bridge is unbalanced, and the motor shaft i5 is: at one limit of its angular movement, and all of the mercury switches are open. Upon turning on the current, the motor immediately begins to run, thus tilting the mercury switches in sequenee and energizing one after another of the: heating elements, until allof said elements have been energized. The motor then comes torest against the limit switch, the shaft occupying'its'.

other extreme angular position.

The boiler now rapidly heats up, and in a few minutes the tem erature will. r h the maxi-- mum safepoint, say 200 F. W :1 this occurs the switch members 55 and 5'? of the are automatically moved upward, thus closing the blue circuit and breaking the connection between-the red and white circuits. This has the effect of immediately unbalaneing the bridge, and the relay operates in such a manner as to cause the motor to run in a; direction to tilt the mercury switches so as to open the circuit of all of the heating elements in sequence. Thus all of the heating elements are momentarily deenergized. A few minutes later, when the temperature of the water falls to, say; 190 F., the aquastat resumes its normal position, and thereupon the motonstarts up again and begins" energizing the heating elements one after an; other. If the room-thermostat is" not satisfied by this time, all of the heating elements are again energized so as to rapidly bring the water up to the maximum temperature. This cycle may occur several times before the air in the rooms has reached the desired temperature.

As soon as the desired temperature is reached,

the thermostat assumes full control, or in other Words takes the control way from the aquastat, which remains quietly in its normal position. As the thermostat calls for more heat the bridge becomes slightly unbalanced, and the relay closes the motor circuit so as to cause it to begin to energize the heating elements in sequence. The motor shaft I5, however, turns so slowly, and the water in the boiler is heated so rapidly, that usually by the time two or three of the heating elements have been turned on the bridge is balanced and the motor stops. If by chance the rooms become too hot, then the reverse operation takes place. The bridge becomes unbalanced in the opposite sense and the motor is caused to run in such a direction as to deenergize the heating elements one after another until the desired room temperature occurs.

Thus the room thermostat normally exercises full control, with the aquastat standing guard to prevent the water temperature from reaching a dangerously high degree.

The operation of our improved system is in sharp contrast to that of the conventional house heating systems, such as are fired by gas or oil. In these conventional systems, when the thermostat calls for more heat, the fire is turned on in full force, and the temperature is likely to overrun that for which the thermostat is set. In our system, on the contrary, when the thermostat calls for more heat, the modulating motor is caused to turn on only a small part of the full heating capacity, just enough to compensate for the slight drop in room temperature which has occurred. In other words, the heat is applied to the boiler progressively, and is cut off when precisely the amount of heat called for by the thermostat has been supplied. Thus there is no overruning. The thermostat may be arranged so that a variation of a fraction of a degree will unbalance the bridge sufnciently to cause the motor to turn on one or more of the heating elements. These may remain on for a few minutes and then be cut oil just as soon as the desired temperature is restored. Thus it will be seen that in order to maintain the normal temperature in the rooms, the boiler is subjected to only a gentle partial heating, that is to say a fraction of the total capacity of the heat generating means, instead of the full capacity as in conventional systems.

What we claim is:

1. Electrical hot water house heating apparatus comprising a rigid panel constructed to be secured flat against a wall of the house, a boiler mounted on the front of the panel, a plurality of electric heating elements in said boiler, sequential controlling mechanism for said elements also mounted on the front of said panel, and wiring connecting said controlling mechanism with said heating elements and carried on the back of said panel, and a cover plate secured to the back of said panel and enclosing said wiring.

2. Electrical hot water house heating apparatus comprising a rigid panel constructed to be mounted fiat against a wall of the house, a boiler mounted on the front of the panel, electric heating elements in said boiler, controls for said elements also mounted on the front of said panel, and wiring connecting said controls with said heating elements and carried on the back of said panel, a receptacle mounted on said panel and connected with said wiring, a room thermostat in the house, and a plug connected with said thermostat and adapted to be inserted in said receptacle.

3. Apparatus constructed to be connected with a hot water house heating system including an electrically driven circulating pump and a room thermostat, said apparatus comprising a rigid panel, a boiler mounted on said panel and having therein a plurality of electric heating elements, controls for said elements mounted on said panel, wiring between said controls and said elements carried wholly by said panel, a pump aquastat mounted on said boiler and connected with said wiring, a pair of receptacles mounted on said panel and also connected with said wiring, and plugs connected respectively with said circulating pump and room thermostat and adapted to be inserted in said receptacles.

4. As an article of manufacture, a rigid panel constructed to be secured against a vertical wall and having mounted thereon an upright boiler provided at its top and bottom with pipe fittings, a plurality of electric heating elements in said boiler, a switch box, a fuse box and a control box all mounted on said panel, a switch in said switch box, fuses in said fuse box, a sequential controller in said control box, and wiring connecting said heating elements with said fuses and said controller, all of said wiring being carried entirely on said panel, the whole article thus constituting a completely assembled, selfcontained unit adapted to be connected with electrical supply mains and with the circulating pipes of a house heating radiator system.

5. As an article of manufacture, an assembled unit comprising a panel having a boiler mounted thereon, the side Walls of said boiler being extended below the bottom wall thereof to form a recess, electric heating elements mounted in and extending through said bottom wall up into the boiler, said extended side walls having openings therethrough and said panel having corresponding openings therein at a point behind said boiler, means mounted on said panel for controlling the supply of current to said heating elements, and wiring connecting said heating elements with said controlling means, said wiring lying within said recess below said bottom wall of the boiler, and passing through said openings in said extended side walls and said panel to the back of said panel, whereby said wiring is wholly concealed.

6. In an electric hot water house heating system, and in combination, a boiler, a plurality of independent electric heating elements therein, control means for energizing and deenergizing said heating elements one after another in sequence, a room thermostat governing said control means, whereby a variable number of said heating elements are normally energized in accordance with the demand for heat, and means in addition to said thermostat for preventing any of said elements from being energized if the water in the boiler is above a predetermined temparature.

7. In an electric hot water house heating system, and in combination, a boiler, a plurality of independent electric heating elements therein, a separate switch for controlling the supply of current to each heating element, a modulating motor for operating said switches in sequence, one after the other, a room thermostat electrically connected with said motor and governing the same in such manner as to normally cause it to close a variable number of said switches in accordance with the demand for heat, and an aquastat subject to the temperatuer of the water in the boiler and interposed in the electrical connections between said motor and said thermostat, said aquastat serving to cause said motor to open all of said switches whenever the water temperature exceeds a predetermined degree, regardless of the demand for heat by said thermostat.

8. In an electric hot water house heating system, and in combination, a boiler, a plurality of independent electric heating elements therein, control means for energizing and deenergizing said heating elements one after another in sequence, automatic means whereby, when first starting up the heating system, all of said elements are energized to quickly heat the water in the system, means whereby, after the house has become warm, only a' few of said elements are energized in response to the variable demand for heat to maintain the desired temperature, and means for deenergizing all of said elements upon the attainment of a predetermined temperature by the water in said boiler.

JOSEPH J. ROUIS. ROBERT J. ROUIS.

REFERENCES CITED The following references are of record in the file of this patent:

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